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Rangerfinder accuracy


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Hi everyone,

I just reentered the Leica M world with a used M10-R and 35mm Summcron ASPH. 

Anyway when just getting a M, it’s easy to get caught up running around shooting test shots to check for focus/rangefinder accuracy.

How much do you worry about this? Do you just shoot and enjoy, and only worry about rangefinder calibration, if things seems really off in real life? I.e. don’t worry about pixel peeping at 100%, and just view the overall image.

Or do you check rigorously and send for calibration at Leica, if at any doubt? And I guess, even after calibration, one can think how long will it stat perfect?

My question is perhaps more simply, what level of accuracy/tolerance is to be expected in real life shooting (reportage, documentary, etc) with many moving parts at play including movement of photographer, subject and maybe rangefinder being accurate down to some tolerance (how precise is that tolerance?)?

Hope it makes sense. I just dont want to end up spending more time worrying about accuracy of my rangefinder (and driving myslef crazy in the process 😉) than on just enjoying and taking photos.

Thank you.

Best,

Mads

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Mcpallesen,   I have been shooting Leica Ms for two decades.  I rarely had a rangefinder issue.  Leica redesigned and made the  M10 series rangefinder far more robust and less prone to coming out of calibration.  You can check your rangefinder and compare your results to using live view focus.  But with a 35mm Cron you won't really see it.  Besides the rangefinder is very accurate.  In essence, you are worrying about nothing.  Your M10-R albeit previously owned, should be fine.  If not and you live in say the USA, you can send it to Don Goldberg at DAG Camera and he can check and calibrate your rangefinder if you think its out of calibration.  He does excellent work, very timely and less expensive than Leica NJ.  I send all my M gear out warranty to Don.  Try:  www.dagcamera.com   Frankly, I suggest you get out and shoot, shoot shoot your M camera and enjoy creating masterpiece photographs.  Hope this helps.  r/ Mark 

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Mads,  Your M10-R is a superb camera along with the 35mm Summicron.  I am certain you will find using your Leica rangefinder camera lets you spend more time creating superb photographs and far less time concerned with controls and features that many photographers never use.  When you photograph people, many will feel at ease and think its a retro camera and your resulting photographs will be far more natural.  Perhaps we will one day see your superb photographs on the forum image threads.  Keep creating and enjoy capturing those moments in time.  r/ Mark

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In my experience the vast majority of "rangefinder inaccuracy" is user mistake (including myself). The most common undetected error is  looking through the viewfinder skewed and not in the optical axis. In fact, although the M10 rangefinder is the most precise and stable one ever built by Leica, the better eye relief makes this specific error easier to make.

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It’s mainly when test shooting at closer static items, I can drive myself crazy with whether focus is spot on or there’s slight back or front focus. But I guess here it will always be down to tolerances and movement of the photographer and might not at all be rangefinder out of calibration.

Thanks for all the replies and encouragements. It feels good to be back with a M again. 😊

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To the OPs question, if I am buying a new or used camera, from a reputable dealer, I’m still checking to make sure focusing is aligned. Why wouldn’t we?

Like many on here I’ve bought and sold an enormous amount of Leica gear and I’d say 70% of gear has been fine. 
 

Testing shouldn’t be some major ordeal. Artins suggestion of using the rear screen for M10R is adequate. Take a static subject, say a street sign with words, focus on a specific letter, zoom in and check focus. With your 35, zoomed in, you will be able to tell if it’s spot on, front or back focuses. Rinse and repeat a few times to eliminate user error. For me it’s always super obvious when something is off. But, I would never not test a fully manual camera that I just bought. 
 

I’d wager a good deal of money that at least 25% of users on here have gear that is out of alignment and have no clue.😎😂

Edited by dkmoore
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Only thing I’d add to this is to use a tripod for testing to minimize user error. For me, practical shooting and printing ultimately tells the story. Chance are there is nothing to fix, if my 35+ years using the M system is any indication. 

Jeff
 

 

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To the original question: if you are sure the focus is spot on through the rangefinder when taking the picture, then if you view the image at 100% the focus should be absolutely spot on as well, especially with a Summicron 35 lens. Anything other than that suggests a check on alignment, usually the body is a little off. Yes, a tripod is preferable when doing the tests. 

In my experience focusing with my Summilux 50 black chrome wide open using the RF has been no issue. But focusing a Summilux 75 proved to be significantly more difficult, for me. 

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On 12/1/2021 at 6:26 PM, jaapv said:

The most common undetected error is  looking through the viewfinder skewed and not in the optical axis. In fact, although the M10 rangefinder is the most precise and stable one ever built by Leica, the better eye relief makes this specific error easier to make.

True - although the high-eyepoint M10 is still better than the Konica Hexar RF .60x finder, which had this same problem in spades. Great camera, so long as one never went longer/faster than a 50mm at f/2.8.

Another tricky bit of user psychology is figuring out if one tends to count the images as "aligned" when they merge - or a mm of ring movement later, when they de-merge again. There can be a slight "dead space" in between, unless one has superb close vision or a magnifier, which can be enough for error if one is close at larger apertures. I've trained myself to always focus "in from infinity" and stop at the instant the images merge - otherwise I get front-focus. Although that is only really critical with the 135 at f/4 or the 75 at f/1.5-2.0

OTOH I checked a 75mm at f/2.0 once, and the available accuracy (carefully used) was such that the RF could distinguish between 200 meters/yards and "infinity." And pick one person out sharply from the background.

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There is a trick for that. Once the images merge one can observe that there is one spot in which the contrast in the rangefinder patch "jumps"; that is the point of perfect alignment.  I agree with always focusing from infinity. It standardizes any tolerance play that might be present. 

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5 minutes ago, mcpallesen said:

Totally agree, I always focus from infinity to subject distance. Definitely the fastest, as you always know to only turn in one and same direction every time.

Works for me too almost 50 years now.

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Same here.  Infinity in.  I don't hunt either, just turn the focus until I get an image match and shoot.

Starts on the infinity side because I like pulling rather than pushing.

Never even considered having rangefinder checked or whatever (M10P), as the results are satisfactory.  

Who are you shooting for?

 

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My (bought secondhand) 240 had both horizontal and vertical alignment issues 🙄

The horizontal issue was easy to spot, just took long enough to take enough pictures to question why my in focus hit rate was subterranean compared to my M9

Vertical was a bit harder to spot, it was very slight and not obvious in every scenario 

To test horizontal I focus on something far away (the moon, a star) - if the split images align in the VF on the infinity hard stop of the lens then chances are that everything is good

(To test vertical I focus on text up close. If it always looks fuzzy no matter how I focus then something’s not right)

I was never really into this ‘always start from infinity’ modus operandi, more look at the split image and see which way to turn the focus ring

But in the past few months I’ve adopted it, and although my hit rate is the same as before I do find myself not having to hunt for the aligned image as much (depends what I’m focusing on of course)

I’d just shoot with it and see if you find you have a problem. Speaking personally l think looking for problems just creates stress, you can kinda convince yourself there is one when there isn’t (or even find one that would’ve never troubled you but now you know it’s there you can’t stop thinking about)

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1 hour ago, KFo said:

I don't hunt either, just turn the focus until I get an image match and shoot.

A good point - also expressed by a Nat. Geo. Leica photographer at a workshop back in 1999.

Don't rack the focus back and forth trying to find "sharp" vs. "blur." That's a bad habit derived from using ttl "screens" to focus (SLR or mirrorless).

The RF is not "sharper" or "fuzzier" - it is binary (aligned/not aligned, 1 or 0).

As to focusing "far to near" or "near to far," as someone said, just do either one consistently

There is one instance where focusing "near towards far" - I.E. driving the lens inwards towards the camera with finger pressure - may be preferrable. That's with old gear where the RF mechanism (including the push-pull spring-loaded "cam" rods in some teles) may have become cruddy and sticky with dried lubricant.

Applying manual pressure with the fingers to "push in" on the camera's mechanism with the lens cam will be more "definite" and consistent, than relying on spring-pressure to overcome the stickiness when "following" the lens out. But I just make sure never to use "cruddy, sticky, old" lenses ;)

Edited by adan
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